High performance earth-abundant electrocatalysts for hydrogen evolution reaction and other reactions

Abstract

Electrodes for catalyzing electrochemical reactions (e.g., the hydrogen evolution reaction) are provided. The electrode may comprise a ternary pyrite-phase transition metal phosphochalcogenide (e.g., CoPS) disposed on a substrate, wherein the ternary pyrite-phase transition metal phosphochalcogenide is a solid material of a ternary compound of a transition metal, phosphorous (P), and a chalcogen, the solid material characterized by a substantially single, ternary alloy phase having a pyrite crystal structure. Methods of using and making the electrodes are also provided.

What is claimed is: 
     
         1 . An electrode for catalyzing an electrochemical reaction, the electrode comprising a ternary pyrite-phase transition metal phosphochalcogenide disposed on a substrate, wherein the ternary pyrite-phase transition metal phosphochalcogenide is a solid material of a ternary compound of a transition metal, phosphorous (P), and a chalcogen, the solid material characterized by a substantially single, ternary alloy phase having a pyrite crystal structure. 
     
     
         2 . The electrode of  claim 1 , wherein the chemical species at the surface of the solid material are substantially the same as the chemical species in the bulk of the solid material. 
     
     
         3 . The electrode of  claim 1 , wherein the ternary pyrite-phase transition metal phosphochalcogenide is a ternary pyrite-phase cobalt phosphochalcogenide, a ternary pyrite-phase nickel phosphochalcogenide, or combinations thereof. 
     
     
         4 . The electrode of  claim 1 , wherein the ternary pyrite-phase transition metal phosphochalcogenide is ternary pyrite-phase cobalt phosphosulfide, ternary pyrite-phase cobalt phosphoselenide, ternary pyrite-phase nickel phosphosulfide, ternary pyrite-phase nickel phosphoselenide, or combinations thereof. 
     
     
         5 . The electrode of  claim 1 , wherein the ternary pyrite-phase transition metal phosphochalcogenide has a formula MPX, wherein M is a transition metal selected from Co, Ni, Fe, and Mn; P is phosphorous; and X is a chalcogen selected from S, Se, and Te. 
     
     
         6 . The electrode of  claim 5 , wherein M is a transition metal selected from Co and Ni; P is phosphorous; and X is a chalcogen selected from S and Sc. 
     
     
         7 . The electrode of  claim 5 , wherein the ternary pyrite-phase transition metal phosphochalcogenide is CoPS, CoPSe, NiPSe, or combinations thereof. 
     
     
         8 . The electrode of  claim 7 , wherein the NiPSe is Se-doped NiP 2 . 
     
     
         9 . The electrode of  claim 1 , wherein the solid material is in the form of nanostructures. 
     
     
         10 . The electrode of  claim 9 , wherein the nanostructures are nanoparticles, nanowires, nanoplates, or combinations thereof. 
     
     
         11 . The electrode of  claim 1 , wherein the substrate is a carbon substrate, a metal substrate or a glass substrate. 
     
     
         12 . The electrode of  claim 1 , wherein the substrate comprises a semiconductor capable of absorbing light to produce free electrons. 
     
     
         13 . The electrode of  claim 1 , wherein the transition metal is alloyed with one or more other transition metals such that the ternary pyrite-phase transition metal phosphochalcogenide is an alloyed ternary pyrite-phase transition metal phosphochalcogenide. 
     
     
         14 . The electrode of  claim 13 , wherein the alloyed ternary pyrite-phase transition metal phosphochalcogenide has a formula M 1 M 2 PX, wherein M 1  and M 2  are transition metals independently selected from Co, Ni, Fe, and Mn; P is phosphorous; and X is a chalcogen selected from S, Se, and Te. 
     
     
         15 . An electrochemical reaction system comprising a reaction cell configured to contain a fluid comprising an oxidant to be reduced; the electrode of  claim 1  in contact with the fluid; and a counter electrode. 
     
     
         16 . A method for catalyzing an electrochemical reaction, the method comprising: exposing an electrode to a fluid comprising an oxidant to be reduced in the presence of free electrons, wherein the electrode comprises a ternary pyrite-phase transition metal phosphochalcogenide disposed on a substrate, wherein the ternary pyrite-phase transition metal phosphochalcogenide is a solid material of a ternary compound of a transition metal, phosphorous (P), and a chalcogen, the solid material characterized by a substantially single, ternary alloy phase having a pyrite crystal structure, whereby the free electrons induce the reduction of the oxidant at the ternary pyrite-phase transition metal phosphochalcogenide-fluid interface to form a reduction product. 
     
     
         17 . The method of  claim 16 , wherein the free electrons are generated by applying an electrical potential across the electrode and a counter electrode in electrical communication with the electrode. 
     
     
         18 . The method of  claim 16 , wherein the substrate comprises a semiconductor capable of absorbing light to produce free electrons, and further wherein the free electrons are generated by exposing the electrode to the light. 
     
     
         19 . The method of  claim 16 , wherein the electrochemical reaction is the hydrogen evolution reaction, the fluid is an aqueous electrolyte solution, the oxidant comprises hydrogen ions, and the reduction product comprises hydrogen gas. 
     
     
         20 . A method for making an electrode, the method comprising exposing a transition metal-containing precursor disposed on a substrate to a chalcogen-phosphorous atmosphere at an elevated temperature and for a period of time sufficient to convert the transition metal-containing precursor to a ternary pyrite-phase transition metal phosphochalcogenide, wherein the ternary pyrite-phase transition metal phosphochalcogenide is a solid material of a ternary compound of a transition metal, phosphorous (P), and a chalcogen, the solid material characterized by a substantially single, ternary alloy phase having a pyrite crystal structure.